The geometry of natural selection in cave and spring populations of the amphipod Gammarus minus Say (Crustacea: Amphipoda)

The shape of the fitness function was investigated in a spring population (Davis Spring) and a cave population (Organ Cave) of the amphipod Gammarus minus in southern West Virginia. The first three principal components of a series of size, antennal and eye measurements and two fitness components (amplexus and number of eggs) were investigated. Smoothing splines using generalized cross-validation scores were found as were least-squares quadratic regression equations. Confidence intervals on shape, as determined by a smoothing parameter, were calculated using a bootstrap approach. Out of 18 cases, there were six cases of no selection, six cases of directional (monotonic) selection, one case of stabilizing selection, one case of disruptive selection, and four cases of selection with multiple internal maxima and minima. Selection on the cave population was frequently directional (5), resulting from strong directional selection for increased size, larger antennae, and smaller eyes. Selection on the spring population, the ancestral habitat for the species, was frequently non-monotonic (five cases) and rarely directional (one case). In both populations, stabilizing selection was rare and no more common than disruptive selection.     

Comparative micromorphology of nectariferous and nectarless labellar spurs in selected clades of subtribe Orchidinae (Orchidaceae)

Floral nectar spurs are widely considered to influence pollinator behaviour in orchids. Spurs of 21 orchid species selected from within four molecularly circumscribed clades of subtribe Orchidinae (based on Platanthera s.l., Gymnadenia–Dactylorhiza s.l., Anacamptis s.l., Orchis s.s.) were examined under light and scanning electron microscopes in order to estimate correlations between nectar production (categorized as absent, trace, reservoir), interior epidermal papillae (categorized as absent, short, medium, long) and epidermal cell striations (categorized as apparently absent, weak, moderate, strong). Closely related congeneric species scored similarly, but more divergent species showed less evidence of phylogenetic constraints. Nectar secretion was negatively correlated with striations and positively correlated with papillae, which were especially frequent and large in species producing substantial reservoirs of nectar. We speculate that the primary function of the papillae is conserving energy through nectar resorption and explain the presence of large papillae in a minority of deceit‐pollinated species by arguing that the papillae improve pollination because they are a tactile expectation of pollinating insects. In contrast, the prominence of striations may be a ‘spandrel’, simply reflecting the thickness of the overlying cuticle. Developmentally, the spur is an invagination of the labellum; it is primarily vascularized by a single ‘U’‐shaped primary strand, with smaller strands present in some species. Several suggestions are made for developing further, more targeted research programmes. © 2009 The Linnean Society of London, Botanical Journal of the Linnean Society, 2009, 160 , 369–387     

Metabolic Inhibitors Block ABA-Induced Stomatal Closure

Closure of stomata of Commelina communis L. leaf epidermis causedby abscisic acid (ABA) was inhibited by sodium azide, potassiumcyanide and hypoxic conditions. Azide was more effective thancyanide at low concentrations, but the cyanide effect couldbe enhanced by addition of salicylhydroxamic acid, providingindirect evidence for cyanide-resistant respiration in epidermaltissue. Azide also inhibited ABA-induced closure of ‘isolated’ stomata and shrinkage of guard cell protoplasts.The results indicate that metabolic energy is required for ABAaction involving solute loss from the guard cells. Possiblemechanisms of action are discussed.     

Luminol-Enhanced Chemiluminescent Response of Human Melanocytes and Melanoma Cells to Hydrogen Peroxide Stress

The response of human melanocytes and melanoma cells to hydrogen peroxide stress was measured. Cells were exposed to glucose/glucose oxidase or free H₂O₂ and reactive oxygen species measured by luminol-enhanced chemiluminescence. The response was distinctly different between the two types and the addition of superoxide dismutase to melanoma cells paradoxically enhanced the chemiluminescent signal. These findings coupled with other known differences between the way these two types of cells handle oxidative stress at a molecular level suggests that a therapeutic window may be avail-able for exploitation.     

Anatomical Changes Which Occur in Cuttings of Agathis australis (D. Don) Lindl 2. The Initiation of Root Primordia and Early Root Development

Cuttings of Agathis australis undergo complex anatomical changesin the sub-base and base. These changes include wound responsesin addition to the processes leading to adventitious root production.Although the root pnmordia form in the mid cortex the firstevents are associated with divisions in the interfasicular regiona few millimetres above the base of the Cutting. This is followedby differentiation into tracheids and phloem which then areoutwards and downwards into the mid cortex. When the inducedvascular strand is only a few cells wide, conditions at theadvancing front are most favourable for primordium formation.If sheets of vascular tissue occur, there is neither the spacenor the focal point for primordia to initiate. In cuttings fromolder material there are abundant resin canals, sclerenchymaand branch traces. These may reduce the amount of parenchymatissue to such a low level that potential primordial sites areno longer present and root formation is prevented. Organization is not observed until over 1500 cells are presentand at about this stage the beginning of organized cell arrangementcan be seen at the site of the apex of the primordium. Untilthis time the progress towards a primordium could not be saidto be ‘determined’. Although the lag phase before any morphological or anatomicalchanges are observed is variable in duration, the time takenfor the period of tracheid development and then for primordiumorganization and outgrowth is fairly constant, taking about2 weeks for each of the two phases. Evidence suggests that thevariation between species is probably in the duration of thelag phase and in the precise site of origin and pattern of theearly events. Once the primordium has formed the events leadingto root formation are probably similar for most species bothfor adventitious and lateral roots. Agathis australis (D. Don) Lindl, kauri, cuttings, wound responses, vascular connections, root primordia, root anatomy     

Morphological structure and optical properties of the wings of Morphidae

The morphological structure and optical properties of the wings of 14 species of Morphidae have been investigated. Most of the scales of the iridescent species of Morphidae （Lepidoptera） present a very particular structure. The ground scales, responsible for the major part of the optical properties, are covered by a very regular set of longitudinal ridges. The ridges themselves are constituted by a superposition of lamellae that act locally as a multilayered structure. This very specific morphology leads to both interferences and diffraction effects. The first one is responsible of the brilliant blue coloration of the males, while the second one diffracts this colored light at a very large angle. These two phenomena give to the butterfly a very effective long-range communication system. The morphological characteristics of the scales of the various species are presented in detail. Two types of optical measurement were performed on the iridescent wings of 14 different species of Morphidae： spectroscopic measurements under various incidences and gonioscopic measurements for a given incidence angle and wavelength. The first allows a determination of the index of refraction of the cuticular material. The second leads to the drawing of spatial diffraction maps. It shows that most of the reflected light is diffracted laterally over a very large angle （90° 〈 0 〈 120°, according to the different species） and that this repartition depends of the polarization of incident light. As predicted by previous calculations, the dissymmetric structure of the ridge is responsible for the separation of the polarization modes in the various diffraction orders.     

Immunological and biochemical analysis of test matrix proteins in living and fossil foraminifers

The characterization of macromolecules from shell matrix proteins in living organisms is the fundamental first step in establishing molecular phylogenies. This is particularly important if ancient macromolecules will be used for the phylogenies. Approximately 500 individuals of Orbulina universa were picked from plankton tows taken in the Gulf of Mexico during spring 1990. Proteins were extracted from the tests of the individuals, and the molecular weights of the proteins were determined and compared to 2,000–4,000-year old samples. Gel electrophoresis of the soluble matrix (SM) from living O. universa showed at least ten protein bands, while electrophoresis of core-top O. universa showed two protein bands. Dot-immunobinding assays of proteins from living and fossil samples of O. universa , incubated against monoclonal antibodies raised against core-top O. universa SM, demonstrated a reactivity with the two proteins in common. Less reactivity was obtained with living samples of the benthic foraminifers Androsina lucasi and Archaias angulatus and core-top samples of the planktonic foraminifer Neogloboquadrina dutertrei. A partial protein sequence from one shell matrix protein approximately 65kD in size, from core-top Orbulina universa , showed a domain of polyaspartic acid at the NH₂ terminus. This is consistent with data obtained for other matrix proteins found in invertebrates and vertebrates. Sequence data provide insight into the role that the protein may play in the biomineralization of the test and will aid in modelling degradation. □ Foraminifera, test proteins, monoclonal antibodies , Orbulina, Androsina, Archaias, Neogloboquadrina, biomineralization, Dot-immunobinding assay, protein sequence.     

Burying beetles: intraspecific interactions and reproductive success in the field

Abstract. 1. The discovery and utilization of small carcasses by burying beetles (Silphidae, Nicrophorus ) was studied by placing dead mice at random points on large grids at two Iocations in Michigan, U.S.A.
2. The majority of mice are found within 24 h by more beetles than ultimately will utilize the carcass. If a carcass is likely to be usurped by a larger species of beetle or by a vertebrate, then intraspecific competition may be postponed until the carcass is concealed and buried.
3. Both males and females practice parental care. Maturing broods are tended by no adults, a single female, a single male, or a male—female pair. No differences in brood success were observed among these categories.
4. The female lays a larger clutch than ultimately will survive. Brood size is regulated after the egg stage, such that offspring number varies, but individual offspring size does not.
5. A large amount of unexplained variation exists in brood size, in both the laboratory and the field. This variation is probably caused by the environment, and not the reproductive physiology of the beetles. Competition with microbes is a likely candidate.
6. Differences exist not only between Nicrophorus species, but also between localities for a single species, suggesting adaptation to local environments.     

Laboratory evaluation of cyromazine against insecticide-resistant field strains of Musca domestica

A screening programme was undertaken to examine the possibility of cross resistance occurring between cyromazine and conventional insecticides. The responses of nine strains of Musca domestica to treatment with cyromazine, trichlorphon, methomyl and pyrethrins with piperonyl butoxide were measured. No tolerance to cyromazine was found, neither was there a direct correlation between larval responses to cyromazine and adult responses to other insecticides. Cyromazine is a potent larvicide against M. domestica and the results of these tests show that it has good potential for the control of houseflies with high levels of resistance to other insecticides.